This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

Page 1 of 7 

To: Savannah River Site Work Group

From: John Cardarelli

Subject: NIOSH Response to SC&A paper “Matrix Issues 22 and 23 Regarding 

Petitioner External Dose Issues”

Date: April 11, 2023

In an SC&A draft memo “Matrix Issues 22 and 23 Regarding Petitioner External Dose 

Issues” dated January 20, 2011, SC&A defines Savannah River Site (SRS) Special 

Exposure Cohort (SEC) petition SEC-00103 Matrix Issues 22 and 23 [SC&A 2011]. The 

two matrix issues are closely related and based on SC&A’s interpretation of worker 

interviews and petitioner statements.

Matrix Issue 22

SC&A worker interviews suggest that workers kept their badges out of higher 

radiation areas in order not to exceed dose limits, or sometimes CW would be in 

radiological situations without knowing it (one incident is described when workers 

were working with radioactive tools thought initially to be clean) (citation omitted).

[SC&A 2011, PDF p. 2]

Matrix Issue 23

Petitioners raise the issue of working conditions with high dose rates when badge 

dose may have been under-recorded or not recorded (such as weekend work) 

and/or pencil dosimeters were off-scale, or when there are zero doses in the 

record. An issue connected to this would be whether the HPAREH [Health 

Physics Annual Radiation Exposure History] database reflects actual work 

experience. Petitioners also state that in some cases, workers thought they were 

working in clean areas that were then determined to be contaminated (citation 

omitted). [SC&A 2011, PDF p. 2]
Page 2 of 7 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

In general, the National Institute for Occupational Safety and Health (NIOSH) has 

addressed the concerns presented in Matrix Issues 22 and 23 with the use of the SRS 

co-exposure model. 

SC&A notes that the adequacy of the external dose records recorded in the HPAREH 

database for use in co-exposure studies associated with construction workers has been 

considered and closed as an SEC issue [SC&A 2011, PDF p. 3]. 

In the process of describing the matrix issues in more detail, SC&A created six

numbered topics that appear to be similar to findings. Each numbered topic is identified 

and summarized below, immediately followed by NIOSH’s response. 

1. Unmonitored Work in Hot Areas Thought to be Clean

Summary: SC&A provides examples of work in hot areas thought to be clean, but later 

turned out to be contaminated. One example includes a large construction project 

above the FB Line occurring between 1984 and 1986 that was treated as a clean area. 

SC&A provides another example of tools that were inadvertently removed from a 

radiation area. The tools were brought to a central repair facility in a truck and later 

found to be contaminated. SC&A also points out that workers in areas assumed to be 

free of radioactive material may not have been routinely monitored. SC&A 

acknowledges NIOSH’s position regarding the practice of carving clean areas out of 

radiation control areas to enable construction projects to proceed with little or no 

personnel monitoring, as detailed in the SEC-00103 Evaluation Report. However, SC&A 

states that it is unclear whether documentation of these cases exists in workers’ 

individual dose records. SC&A questions how a dose reconstructor would know to look 

in the Radiation Survey Log Sheets that describe when and where these practices were 

followed [SC&A 2011, PDF pp. 3–5]. 

NIOSH Response: NIOSH reaffirms the information provided on clean areas carved out 

of radiological control areas and agrees that it is unlikely that this kind of information 

would be included in an individual dose record. Consequently, the dose reconstructor 

would use a co-exposure model for dose reconstruction for any period of time when

monitoring data are not available.

With regard to surface contamination on tools being discovered outside of a zone where 

contamination control monitoring was routinely required, the fact that contamination was 

found in this area demonstrates that SRS had monitoring in place that included surveys 

in areas where radiological operations were not conducted. Surface contamination on 

tools would not present an external dose problem. Contamination of a magnitude large 
Page 3 of 7 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

enough to present an external dose problem would only exist in very highlycontaminated locations that would be under careful control.

With regard to the FB Line construction project example, SC&A states “It would be 

useful to examine the dose records of some of the construction workers who worked on 

the addition above the FB-line to follow-up the information provided by workers 

regarding unmonitored dose” [SC&A 2011, PDF p. 5]. NIOSH does not agree that such 

a study is necessary since the co-exposure model is available and is intended for 

instances in which monitoring data are incomplete or not available. Furthermore, the FB

Line construction is only one example; there were other times when work areas were 

separated to enable construction work. 

2. Compromised Badge Readings

Summary: SC&A cites concerns mentioned in worker interviews and in the SEC 

petition that described common practices that could result in an under-recording or nonrecording of external dose. Two of the examples are associated with non-uniform 

exposure due to badge positioning or shadow-shielding offered by objects in the work 

area. Two other examples involve inadequate monitoring associated with the use of a 

“temporary badge” which is one not assigned to a specific individual but instead taken 

from “a row of leftover badges,” and off-shift workers who worked without monitoring 

because there were no monitoring badges available. SC&A states “NIOSH has not 

provided a dose reconstruction approach for such issues that put into question the 

accuracy of the recorded dose, either because the full extent of the exposure was not 

recorded or because of practices where badges were not worn or were damaged with 

possibly unrecorded doses” [SC&A 2011, PDF p. 6].

NIOSH Response: Unless a worker was in a high-radiation area, it would be typical to 

wear only one badge in a non-uniform exposure scenario. Possible inaccuracies and 

non-uniform exposure are routinely considered in dose reconstruction procedures. By 

default, a dose reconstructor assumes 100% anterior-posterior (AP) exposure geometry

but has the option to assume rotational or posterior-anterior exposure geometry if

Computer Assisted Telephone Interviews (referred to as CATI) or other dose 

reconstruction guidance prompts the dose reconstructor to change from the default 

assumption. This information would include the organ of dosimetric interest. External 

Dose Reconstruction Implementation Guideline, OCAS-IG-001 Revision 3 [NIOSH 

2007] discusses the assumption of 100% AP exposure geometry and concludes that 

when associated with the corresponding AP dose conversion factors, the result, in the 

great majority of cases, does not result in an underestimate of organ dose. The NIOSH-
Page 4 of 7 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

Interactive RadioEpidemiological Program (referred to as IREP) probability of causation 

program input parameters account for the uncertainty in measured dose.

Ample evidence of a comprehensive radiation safety program exists at SRS, including

monitoring for workers’ exposure to external radiation regardless of their employer and 

position. Visitor badges were available on the badge racks to ensure that workers who 

did not routinely work in an area (i.e., visitors to the area) were monitored upon entry 

into the area. These records are available and are included in an individual’s personnel 

monitoring records used for dose reconstruction. Episodes that involved using a 

temporarily-assigned dosimeter, such as the worker described, could have happened, 

but based on the weight of the evidence (i.e., number of visitor badges processed) and 

the attention given to off-normal situations, NIOSH believes this would have been a rare 

event, not typical of the monitoring practices at SRS. In both examples cited, the 

workers’ records would not have included monitoring results for the period of time in 

question and the dose reconstructor would apply data from the co-exposure model.

3. Exposure Geometry and Organ Dose Issues

Summary: Workers said they always wore badges on the chest regardless of the 

exposure direction and said that ring dosimeters were not used when taking samples on 

the HB and FB Lines.

NIOSH Response: Topic 2 above addresses exposure geometry. As necessary, 

NIOSH applies geometric corrections to dose reconstructions. For example, NIOSH and 

the ORAU Team are currently revising ORAUT-OTIB-0017, Interpretation of Dosimetry 

Data for Assignment of Shallow Dose [ORAUT 2005] to include dose relationships that 

have been assessed at Building 772-F for a cohort of approximately 50 employees 

performing work as a “decontamination facility attendant.” This job involved hands-on 

work with plutonium and uranium source terms. The co-exposure data were analyzed 

using the quantile regression methods described in ORAUT-RPRT-0087, Applications 

of Regression in External Dose Reconstruction [ORAUT 2018]. The revised ORAUTOTIB-0017 (Rev. 02) will include relationships for left-hand and right-hand exposures at 

the 50th and 95th percentiles for whole body and shallow dose readings. 

NIOSH will address non-uniform exposures in Savannah River Site – Occupational 

External Dose, ORAUT-TKBS-0003-6.
Page 5 of 7 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

4. Pencil Dosimeter Issues

Summary: Workers reported that pencil-dosimeter failures were occasionally handled 

inconsistently. SC&A notes that pencil dosimeters were not used for dose of record and 

their investigation did not indicate any evidence of a site-wide systematic effort to ignore 

high pencil-dosimeter readings. Therefore, issues related to pencil dosimeters were not 

a significant item.

NIOSH Response: NIOSH concurs.

5. Records of DuPont Operations Workers compared to Construction Trades 

Workers

Summary: This item cites an example of one worker who claimed to be monitored 

differently when he worked for DuPont-Construction versus DuPont-Operations. SC&A 

suggests that NIOSH might conduct a comparison of records of some workers who 

were in construction trades for some time and also in operations at another separate 

time, keeping in mind that to be meaningful an investigation will have to include

determining external exposure potentials in the different jobs as well as examining the 

dose records.

NIOSH Response: NIOSH does not believe a comparison is necessary given the status 

and implementation of Parameters to Consider when Processing Claims for 

Construction Trade Workers, ORAUT-OTIB-0052 [NIOSH 2014]. Monitoring differences 

and exposure differences are why ORAUT-OTIB-0052 was developed. 

6. Overall Petition Challenge to NIOSH

Summary: SC&A quotes a challenge from the President of the Augusta Building and 

Construction Trades Council to NIOSH, “I want to come from this meeting and look our 

members in the eyes and say, NIOSH is being fair to us” [SC&A 2011, PDF p. 9].

NIOSH Response: NIOSH conducts its work in a transparent process with oversight 

provided by the Advisory Board. To ensure that the methods and guidelines NIOSH 

uses in dose reconstruction are as sound as possible, an independent Advisory Board, 

appointed by the President of the United States, reviews and comments on the validity 

and quality of dose reconstructions, dose reconstruction methods, and technical 

documents. 

In cases where radiation exposures in the workplace environment cannot be fully 

characterized based on available data, default values based on reasonable scientific 
Page 6 of 7

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

assumptions are used as substitutes. NIOSH’s dose reconstruction methods 

consistently give the benefit of the doubt to the claimant whenever there is a question or 

uncertainty about the amount of radiation exposure the worker may have received. 

NIOSH provides the public with opportunities to engage in different areas of the Energy 

Employees Occupational Illness Compensation Program Act (EEOICPA) to ensure the 

public that their concerns are heard and incorporated into the EEOICPA process.
Page 7 of 7 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its 

contractor for use in discussions with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, 

interim, and White Paper documents are not final NIOSH or ABRWH (or their technical support and review 

contractors) positions unless specifically marked as such. This document represents preliminary positions taken on 

technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact 

any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

References

NIOSH [2007]. External dose reconstruction implementation guideline. Cincinnati, OH: 

U.S. Department of Health and Human Services, Centers for Disease Control and 

Prevention, National Institute for Occupational Safety and Health. OCAS-IG-001 Rev. 

03, November 21. [SRDB Ref ID: 38864]

NIOSH [2014]. Parameters to consider when processing claims for construction trade 

workers. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for 

Disease Control and Prevention, National Institute for Occupational Safety and Health.

ORAUT-OTIB-0052 Rev. 02, July 24. [SRDB Ref ID: 133862]

ORAUT [2005]. Interpretation of dosimetry data for assignment of shallow dose. Oak 

Ridge, TN: Oak Ridge Associated Universities Team. ORAUT-OTIB-0017 Rev. 01, 

October 11. [SRDB Ref ID: 19434]

ORAUT [2018]. Applications of regression in external dose reconstruction. Oak Ridge, 

TN: Oak Ridge Associated Universities Team. ORAUT-RPRT-0087 Rev. 00, March 13. 

[SRDB Ref ID: 170100]

SC&A [2011]. Matrix issues 22 and 23 regarding petitioner external dose issues – draft. 

Letter to Savannah River Site Work Group. Arlington, VA: SC&A. January 20. [SRDB 

Ref ID: 184209]